Introduction
Phytophthora erythroseptica
var.
erythroseptica Pethybr.
(1913)
Phytophthora erythroseptica
var. erythroseptica was first
described by Pethybridge (1913; 1914) as the causal organism of pink rot of
potatoes in
Cultural Characteristics
The minimum temperature for growth is 2.5°C, the optimum temperature for growth
is 27.5°C, and the maximum temperature for growth is 34°C
(Fig. 3).
Reproductive Structures
Asexual Structures
Sporangiophores:
Sporangiophores are sympodial and branch immediately below the
sporangium. Sporangia proliferate internally through empty sporangia.
Sympodia form in water.
Sporangia:
Sporangia are
nonpapillate, vary from ellipsoid or ovoid to a distorted shape, and are
often constricted in the middle. They are
noncaducous. Sporangia are
26–47
× 43–69 µm (average
27.2
× 44.2 µm) with a round or
tapered base (Fig. 4b). The length–breadth ratio is greater than 1.6.
Chlamydospores:
Chlamydospores have not been found.
Hyphae:
Hyphae are uniform, fine, and less than 8 µm.
Rounded or angular swelling occurs in water.
Sexual Structures
P. erythroseptica
is
homothallic.
Antheridia:
Antheridia are
amphigynous, elongated, ellipsoidal, or cylindrical and 13 × 14 µm in
diameter. Oogonia with multiple antheridia (two to four) have been observed.
Oogonia:
Oogonia are smooth walled and 30–46 µm in diameter (average 34.9 µm).
Oospores:
Oospores are aplerotic and 28–35 µm in diameter (average 30.5 µm) with a thick wall (2.5 µm) (Figs. 4a and 5).
Host Range and Distribution
Host |
Common Name |
Disease |
Geographical Distribution |
Atropa belladonna |
Belladonna |
Root rot; damping-off; seedling rot |
|
Brassica oleracea |
Kale, cabbage, turnip |
Root rot |
|
Carduus arvensis |
Creeping thistle |
Root rot |
|
Calceolaria |
Slipperwort, slipper flower |
Root rot |
|
Cymbidium |
Orchid |
Root rot; leaf spot |
|
Cynosurus cristatus |
Crested dogtail |
Root rot |
|
Hordeum vulgare |
Barley |
Root rot |
|
Leymus chinensis |
Chinese lyme grass |
Crown and root rot |
|
Lolium multiflorum |
Ryegrass |
Root rot |
|
Lycopersicon esculentum |
Tomato |
Fruit rot |
|
Phleum pratense |
Timothy |
Root rot |
|
Plantago media |
Plantain |
Root rot |
|
Saccharum officinarum |
Sugarcane |
Seed piece rot |
|
Secale cereale |
|
Root rot |
|
Senecio cruentus |
Cineraria |
Wilt |
|
Solanum tuberosum |
Potato |
Pink tuber rot |
Ireland, Netherlands, United Kingdom, Indonesia, Bulgaria, Canada,
Australia, United States, India, New Zealand, Yugoslavia, Tasmania,
Egypt, Peru, Iran |
Spinacia oleracea |
Spinach |
Seedling rot |
|
Trifolium |
Clover |
Root rot |
|
Tulipa |
Tulip |
Root rot; shanking |
|
Tussilago farfara |
Coltsfoot |
Root rot |
|
Vicia faba, V. sativa |
Broad bean, spring vetch |
Root and crown rot |
|
Zantedeschia
|
White, yellow, or pink calla; arum lily |
Rhizome rot; leaf and petiole blight |
|
Symptoms
The pathogen has been misidentified as the causal organism of red raspberry root rot. P. fragariae var. rubi is now recognized as the cause of raspberry root rot.
Pink Rot or
Tuber Rot of Potato:
Pink rot occurs in potato tubers primarily, but the disease can affect stems, stolons, roots, and leaves of potato. Affected tubers have a dull brown appearance, and the lenticels and eyes turn dark brown (Fig. 6). Decay usually begins at the stem end of the tuber. When the tuber is cut, the exposed surface turns deep salmon pink after 30–45 min (Figs. 7 and 8). Potato tubers become tough and leathery after infection (Fig. 9). Dormant oospores initiate disease from infested soil (Erwin and Ribeiro, 1996) (Fig. 10).
Seed-Piece
Rot of Sugarcane:
Infection of sugarcane stem pieces in
References
Alcock, N. 1926. A preliminary note on a
Phytophthora on Atropa belladonna.
Pharm. J. 116:232.
Bywater, J., and Hickman, C. J. 1959. A new variety of
Phytophthora erythroseptica, which causes a soft rot of pea roots. Trans.
Br. Mycol. Soc. 42:513-524.
Cline, E. T., Farr,
D. F., and Rossman, A. Y. 2008. A
synopsis
of Phytophthora with accurate scientific names, host range, and
geographic distribution. Plant Health Progress. doi:10.1094/PHP-2008-0318-01-RS.
Cooke, D. E. L., Drenth, A.,
Dastur, J. F. 1948. Phytophthora
species of potatoes (Solanum tuberosum)
in the Simla Hills. Indian Phytopathol. 1:19-26.
Erwin, D. C., and Ribeiro, O. K.
1996.
Phytophthora Diseases Worldwide. American Phytopathological
Society,
Ho, H. H., and Jong, S. C.
1989.
Phytophthora erythroseptica. Mycotaxon 36:73-90.
Kroon, L. P. N. M., Bakker, F. T., van den Bosch, G. B. M., Bonants, P. J. M.,
and Flier, W. G.
2004. Phylogenetic
analysis of
Phytophthora species based on mitochondrial and nuclear DNA
sequences. Fungal Genet. Biol. 41:766-782.
Pethybridge, G. H. 1913. On the rotting of potato tubers by a new species of
Phytophthora having a method of sexual reproduction hitherto undescribed.
Sci. Proc. R.
Pethybridge, G. H. 1914. Further observations on
Phytophthora erythroseptica Pethybr. and on the disease produced by it in
the potato plant. Sci. Proc. R.
Stamps, D. J.
1978.
Phytophthora erythroseptica. CMI Descr. Pathog. Fungi Bact.
593:1-2.
Stamps, D. J., Newhook, F. J., Waterhouse, G. M., and Hall, G. S. 1990. Revised
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Phytophthora de Bary.
Mycol. Pap. 162. CAB International,
Wallingford, United Kingdom; Commonwealth Mycological Institute, Kew,
van
der Zwet, T., and Forbes, I. L. 1961. Phytophthora megasperma.
The principal cause of seed-piece rot of sugarcane in
Waterhouse, G. M. 1963. Key to the species of Phytophthora de Bary. Mycol. Pap. 92.
CAB International, Wallingford, United Kingdom; Commonwealth Mycological Institute, Kew,
Wharton, P., and Kirk, W. 2007. Pink Rot. Michigan Potato Diseases Series. Mich. State Univ. Ext. Bull. E-2993. www.potatodiseases.org/pinkrot.html.